Overnight 12 hr secretory growth hormone studies(ICGH)(q 20 minutes) are compared to provocative GH studies(PGH) peak GH release in children with slow growth velocity. Subjects are divided into four categories: normal (N)/N; N/low; low/N and low/low with respect to PGH/ICGH respectively. Response to GH treatment is compared by category in those children who are entered into GH treatment programs.